Conventional golf balls can be divided into two general classes: solid and wound. Solid golf balls include one-piece, two-piece (i.e., solid core and a cover), and multi-layer (i.e., solid core of one or more layers and/or a cover of one or more layers) golf balls. Wound golf balls typically include a solid, hollow, or fluid-filled center, surrounded by a tensioned elastomeric material, and a cover. It is also possible to surround a hollow or fluid-filled center with a plurality of solid layers. Solid balls have traditionally been considered longer and more durable than wound balls, but many solid constructions lack the “feel” provided by the wound construction.
More recently, by altering ball construction and composition, manufacturers have been able to vary a wide range of playing characteristics, such as compression, velocity, “feel,” and spin, optimizing each or all be optimized for various playing abilities. In particular, a variety of core and cover layer(s) constructions, such as multi-layer balls having dual cover layers and/or dual core layers, have been investigated and now allow many non-wound balls to exhibit characteristics previously unattainable in a solid-construction golf ball. These golf ball layers are typically constructed with a number of polymeric compositions and blends, including polybutadiene rubber, polyurethanes, polyamides, and ethylene-based ionomers.
It is well known in the golf ball art as well as in the polymer and rubber science that conventional butyl rubber is typically an energy absorbing material, hence its vast use in applications such as a shock absorbing medium, this characteristic reduces the resiliency of the golf ball as in the case of developing a low flight golf ball. The use of butyl rubber in golf balls has not been fully explored since it's been found that even a small amount of butyl rubber will significantly reduce the golf ball resiliency and performance. There is a need in the golf ball industry to find a way to overcome this deficiency. The present invention introduces a new ball construction and attacks the above deficiency by forming golf ball layers with partially or fully neutralized butyl ionomers which are developed by carrying out a halogenation process to produce a halobutyl polymer followed by a nucleophilic reaction with the allylic halide functionality to produce an ionomer moiety. This is further described in U.S. Patent Publication 2007/0218296.